Aimed at defending the GOP-led legislature's budget, the ads aired by the Americans for Prosperity Foundation and the Civitas Institute claimed, among other things, that the GOP "added state funding for 2,000 more teachers."

Given that the number of teachers in NC actually declined by 915 over the last year, FactCheck.org denounced the ad's "inflated figures" and "faulty assumptions." The local Raleigh News & Observer echoed that "the ad could leave viewers with a false impression.”

But the ad (watch it here) had another potential problem: It specifically called out Democratic Gov. Beverly Perdue, which could create problems with state election laws. The ad starts with this statement:

Who can afford a billion-dollar tax increase in times like these? Governor Perdue thought we all could, but hard working families like ours said ‘no.’

FactCheck.org says the claim itself is dubious. But as Bob Hall of the watchdog group Democracy North Carolina points out, singling out Perdue may have also constituted electioneering -- something frowned upon by the Internal Revenue Service, and which would require that the groups to disclose the donors behind the ad.

As Hall observed in a March 22 letter [pdf] to the state election board, because the lame duck NC governor still operates an active campaign committee, she may be legally considered a candidate.

If so, that would trigger a part of the North Carolina General Statute, which says that any ads that "clearly identify a candidate for public office" are considered "electioneering communications" -- and therefore would require that the sponsors disclose their donors.

Americans for Prosperity appears to reject the connection; as an April 2 message from the group's Twitter feed reads:

Deceased #ncga member Vernon Malone still has open campaign account. Does bob hall think he is a candidate? @AFPNC @NCCapitol @NCCivitas

Aside from the legal questions, the use of a 501c3 public charity would also mean that the Kochs and Pope would be essentially using a government subsidy -- the generous tax break afforded to donors to nonprofits -- to further their political agenda.

But this year, big donors have become more brazen, "weaponizing" the once off-limits 501c3 charities to run ads which increasingly push the political envelope. This spring, the Americans for Prosperity Foundation unleashed $700,000 worth of ads praising Wisconsin Republican Gov. Scott Walker as he faced a recall election.

Whoever donated the money to the AfP Foundation for the ads (IRS regulations don't require them to be disclosed) can deduct the gifts from their taxes -- up to $350,000 for every $1 million donated, according to Dan Froomkin at The Huffington Post.

"The thing that I think is different is that in the (c)(3) context, they're really taking money out of our pockets," said Donald Tobin, a law professor at Ohio State University and former tax lawyer at the Justice Department.

"It's making all the taxpayers who don't want to support a particular candidate, in fact, support them," said University of Miami law professor Frances Hill.

The ultimate irony? Americans for Prosperity and the Civitas Institute have led the attack on North Carolina's "Clean Elections" program, which gives grants to candidates who commit to small-donor fundraising -- on the grounds that it amounts to "taxpayer funded elections."

Apparently, that's not a problem as long as the Kochs and Pope are the ones getting a handout.